blow off valve?

hey sorry if this is somewhere in this forum but im about to get a 96 riviera and i was wondering if, where, and how i could get a blow off valve for it....i know that theyre for turbos and i think that theyre for superchargers too but im not sure....how do i put one on if i can and has anyone else got one for theyre riv?....

if im not mistaken there is already a bypass valve on the s/c version riv's. it works like a blow off valve..i think (i dont know much about turbo applications.) it is closed to build up boost then opens up to let the boost pressure drop. ours is open most of the time durring driving but closes to get more power when you give more than like 1/2 throttle. you can not get the same sound that a turbo blow off has (pssst) but the s/c series II can eat most rice with a small turbo :) why would you want a blow off valve for the riv if not for the sound?